[1.7.2] Giving entityPlayer a Random Item

[SilentThief]

Hello, I am having a bit of trouble giving the person right clicking my item, a random item out of the Minecraft Vanilla Items. Here's my code so far:

 

public ItemStack onItemRightClick(ItemStack itemStack, World world, EntityPlayer entityPlayer) {

	if (entityPlayer.capabilities.isCreativeMode) {
		return itemStack;
	}else {

		--itemStack.stackSize;

		entityPlayer.inventory.addItemStackToInventory(new ItemStack(itemRand, 1));

	}

	return itemStack;
}

}

 

itemRand is a variable inside of the Minecraft Item class.

[GotoLink]

Item#itemRand ? It is a Random, not a Item.

You would better shuffle through GameData#itemRegistry.

[SilentThief]

So, there's no way to make an ItemStack have a random item set to it, each time it's ran?

[Jwosty]

Well, what are you trying to use this for, ultimately? If you change the item to a random one, then it will most likely end up being a vanilla item. And then you wouldn't be able to change it again from Item#onItemRightClick.

 

You could probably create a custom item that simply takes the texture of another item, changing that item randomly each time it is used.

[SilentThief]

This item is essentially a "reward bag", when you right click the item, it deletes the bag, and gives you a random item.

 

I personally have no idea how to do this, since the itemRand in the Item class cannot be using in the ItemStack method.

[coolAlias]

itemRand is a Random object, meaning you use it to get random numbers - it's not an Item. You can use itemRand to get a random Item from the list of all registered items, or you could make your own list of items you want to give as rewards and select randomly from that. In either case, I suggest you start by brushing up on some basic Java, as it will make your journey much easier.

 

For starters, here is the documentation on the Random class. That will help you figure out how to get a random number

[SilentThief]

I know basic Java. Just very new to modding, don't know how everything works. And yes, I know itemRand isn't an item.

 

I will take your advice and use the object to grab all of the registered items in Minecraft.

[Mecblader]

Osmthing you may be able to do is make a HashMap of all of the Items that can be awarded (this would filter out non-accessible items and give you more customization) Then you could get a random int, from itemRand and get the item stack that corresponds to that item in the HashMap.

[AlexStone]

i think this will work good

add this and replace itemrand with stack

Random r = new Random();
ItemStack stack = new ItemStack(Item.itemList[r.nextInt(Item.itemList.length) + 1], r.next(3 /*MAX QUANTITY*/) /* this will generate random quantity */)

hope this work!

[SilentThief]

@Mecblader Thank you for your suggestion, I will try hash maps if I don't find a better solution to this.

 

@AlexStone There are a few issues with that code.

1. Where are you getting itemList from?

2. Where are you getting r.next from?

I'm guessing r.nextInt();

[SilentThief]

Yea, using a random each time crashes the game.

 

I tried using the code AlexStone provided, with a custom itemList I created. It does crash the game.

 

Even if I were to do:

 

ItemStack stack = new ItemStack(ItemList.itemList[r.nextInt()];

It would still end up crashing the game.

 

I will try a few other things, see if they work.

[TLHPoE]

I haven't tested this code yet, so yeah:

public static Item getRandomItem() {
	Item i = null;
	Object[] objects = Item.itemRegistry.getKeys().toArray();
	Object select = objects[utilRF.RANDOM.nextInt(objects.length)];
	if(select instanceof Item) {
		i = (Item) select;
	} else {
		return getRandomItem();
	}
	return i;
}

 

UtilRF.RANDOM is a Random object.

[SilentThief]

If you return getRandomItem(); it ends up creating a loop crashing the game. Removing it causes the whole method to do nothing.

[TLHPoE]

It only returns it if the object isn't an instance of an item, which is unlikely.

[SilentThief]

It only returns it if the object isn't an instance of an item, which is unlikely.

For some reason it returns it everytime. And, why is there:

UtilRF.RANDOM.nextInt()?

Instead of UtilRF.nextInt()

[jabelar]

While it is nice to use elegant coding, or impressive to use tricky coding, sometimes I think it is best to just do something simple and "brute force".  Why not just do use a random int to pick from a case statement and just list out all the items you want to have possible.  Sure it will be fairly long list (although not really that long), but it will work very simply and should perform well too.  The nice thing is that it is gives full control and won't have any weird occasional issues where you pick some unusable item out of the gameregistry.

[SilentThief]

When you right click this bag, I want it to give you 1 item. The item is chosen from every single item in the game, it would be much more convenient to not have to make 300+ item stacks.

[SanAndreaP]

Define a new List where you store/cache all possible items:

private List<Item> filteredItems = null;

 

In your onItemUse method, do this:

- If the list is uninitialized, initialize it and fill the array with all items:

        if( filteredItems == null ) {
            filteredItems = new ArrayList<Item>();
            Iterators.addAll(filteredItems, Iterators.filter(Iterators.forArray(Item.itemsList), Predicates.notNull()));
        }

The last statement in the block is basically, it filters the itemsList array by throwing out any null value which are in there (basically all unassigned/free items) and adds them to your filteredItems list.

 

- After that, get a random element from your filteredItems list and make a new ItemStack out of that element:

        ItemStack stack = null;
        if( items.size() > 0 ) {
            stack = new ItemStack(items.get(par2EntityPlayer.getRNG().nextInt(items.size())), 1);
        }

 

The only problem I see is that some items have multiple metadata values as subtypes (dyes and potions are the most prominent example) and you'll get only the first item subtype

[TLHPoE]

It only returns it if the object isn't an instance of an item, which is unlikely.

For some reason it returns it everytime. And, why is there:

UtilRF.RANDOM.nextInt()?

Instead of UtilRF.nextInt()

 

I don't use UtilRF.nextInt() because UtilRF doesn't have a method called nextInt. I keep a static Random object in the class whenever I need to use one.

[TLHPoE]

Ok, I've gotten the method to work. It also returns blocks too, since each block has an ItemBlock version.

public static Item getRandomItem() {
	Item i = null;
	int length = Item.itemRegistry.getKeys().toArray().length;
	Object select = Item.itemRegistry.getObjectById(UtilRF.RANDOM.nextInt(length));
	if(select != null && select instanceof Item) {
		i = (Item) select;
	} else {
		return getRandomItem();
	}
	return i;
}

 

100% sure to work, tested.

[SilentThief]

Ok, I've gotten the method to work. It also returns blocks too, since each block has an ItemBlock version.

public static Item getRandomItem() {
	Item i = null;
	int length = Item.itemRegistry.getKeys().toArray().length;
	Object select = Item.itemRegistry.getObjectById(UtilRF.RANDOM.nextInt(length));
	if(select != null && select instanceof Item) {
		i = (Item) select;
	} else {
		return getRandomItem();
	}
	return i;
}

 

100% sure to work, tested.

I got confused on that UtilRF.RANDOM part, I wasn't thinking...lol

Didn't know UtilRF was the class. lol

 

Anyways, testing the code.

 

Doesn't seem as if the code is working, does nothing actually, here is my class:

package com.hex.lootbag;

import java.util.Random;

import com.hex.hexcore.HexCore;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;

public class ItemLootBag extends Item {

public ItemLootBag() {

	setUnlocalizedName("itemLootBag");
	setCreativeTab(CreativeTabs.tabAllSearch);
	setTextureName("lootbag:ItemLootBag");
	setMaxStackSize(1);

}

public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {

	System.out.println("Working!");

	if (player.capabilities.isCreativeMode) {
		getRandomItem();
		return item;
	}else{
		--item.stackSize;
		getRandomItem();
		return item;
	}
}

static Random RANDOM = new Random();

public static Item getRandomItem() {
	Item i = null;
	int length = Item.itemRegistry.getKeys().toArray().length;
	Object select = Item.itemRegistry.getObjectById(ItemLootBag.RANDOM.nextInt(length));
	if(select != null && select instanceof Item) {
		i = (Item) select;
	} else {
		return getRandomItem();
	}
	return i;
}

}

[wojtab]

FTFY

package com.hex.lootbag;

import java.util.Random;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;

public class ItemLootBag extends Item {

public ItemLootBag() {

	setUnlocalizedName("itemLootBag");
	setCreativeTab(CreativeTabs.tabAllSearch);
	setTextureName("lootbag:ItemLootBag");
	setMaxStackSize(1);

}

public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {

	System.out.println("Working!");

	if (player.capabilities.isCreativeMode) {
		player.dropPlayerItemWithRandomChoice(new ItemStack(getRandomItem(), 1), false);
		return item;
	}else{
		--item.stackSize;
		player.dropPlayerItemWithRandomChoice(new ItemStack(getRandomItem(), 1), false);
		return item;
	}
}

static Random RANDOM = new Random();

public static Item getRandomItem() {
	Item i = null;
	int length = Item.itemRegistry.getKeys().toArray().length;
	Object select = Item.itemRegistry.getObjectById(ItemLootBag.RANDOM.nextInt(length));
	if(select != null && select instanceof Item) {
		i = (Item) select;
	} else {
		return getRandomItem();
	}
	return i;
}

}

[TLHPoE]

You didn't give the player anything. The method returns an item, it doesn't automatically give the player the item.

[SilentThief]

You didn't give the player anything. The method returns an item, it doesn't automatically give the player the item.

Sorry, was spacing out, was like 2AM when I looked at that code.